But the assessment was met with skepticism by the United States which has declared any use of chemical weapons
in Syria's two-year-old civil war a "red line" that could trigger intervention.

The Syrian government and rebels each accused the other of launching a chemical attack near the northern city of Aleppo last month.

Syria
last year acknowledged that it had chemical and biological weapons and said it could use them if foreign countries intervened, a threat that was met with strong warnings from Washington and its allies.

Western countries and Israel
have also expressed fears that chemical weapons could fall into the hands of militant groups hostile to them as Assad's authority erodes.

"Even if Syria does have chemical weapons, our leadership and our military
will not use them either against Syrians or against Israelis, above all for moral reasons and secondarily on legal and political grounds," Omran al-Zoubi was quoted by Interfax news agency as saying at a Moscow university.

He said Syria would not resort to chemical weapons even if it had to go to war with Israel and use "all resources".